In typical paving operations, the raw asphalt material is stored in a dump truck or straight truck for transport and is then dumped or pushed into a hopper adjacent the rear of the truck. The hopper then feeds the material to the paving equipment which lays the material as asphalt paving. When involved with this type of operation, it is preferred that the paving material be dumped directly from the truck into the hopper without spilling material onto the surrounding area. Moreover, it is also preferred to use a dump truck instead of a straight truck due to the ability to dump the material using a gravity feed and due to a dump trailer's greater carrying capacity than that of a straight truck.
To accommodate this operation, typically an asphalt hopper is positioned very close to the rear of the dump trailer with the front edge of the hopper underneath the trailer's sill. Spacer wheels can be placed on the hopper which abut the trailer's rear wheels to provide the correct spacing. Prior trailers have allowed the sill to overlap the hopper by having the rear wheels of the trailer set in at least approximately 12 inches or more from the rear edge of the trailer.
Recent federal regulations have required, for safety reasons, that trucks having rear wheels set more than 12 inches from the rear edge of the trailer include rear, shock absorbing bumpers mounted to the rear of the trailer to prevent smaller vehicles from traveling under the trailer in a collision. While desirable from a safety aspect, this also prevents the hopper from extending underneath the trailer sill. To compensate for this problem, paving companies are rebuilding older trailers or some manufactures have proposed folding or collapsible bumpers which are deployed during normal driving and stored during dumping.
In practice, collapsible bumpers have been unwieldy, expensive and have caused customer complaints. An alternate solution is to connect a spill guard to the rear edge of the dump trailer thereby extending the length of the trailer. This solution is unsatisfactory as it essentially violates the federal requirements. A third alternative has been to use a straight trailer, which is not yet subject to the same requirements, but this entails the disadvantage of a smaller load as compared to a dump trailer. Accordingly, there is a need for an improved dump trailer which provides sufficient load capacity and the ability to efficiently transfer paving material from the trailer to the hopper without waste and which complies with federal safety regulations.
A further concern in existing hoppers used with dump trailers is that the extended lip can interfere with the front panel of the hopper. To compensate for this interference, many operators have removed the upper portion of the hopper's front panel to provide clearance, but which simultaneously reduces the hopper's capacity. Accordingly, there is a need for a design in which the front panel of the hopper does not need to be reduced in size.
The present invention addresses these concerns.